1. Field of the Invention
The present invention generally relates to digital signal encoding and for this purpose provides a method and a device for encoding a digital signal. It also relates to a method and device corresponding to the encoding method and device.
The object of the encoding is to compress the signal, which makes it possible respectively to transmit the digital signal and to store it in memory while reducing the transmission time, or the transmission rate respectively, by reducing the space in memory that is used.
The invention is in the field of lossy compression of digital signals. The digital signals considered here are of any type, for example fixed images, video, sound, or computer data.
In what follows, the encoding and decoding of a fixed image will more particularly be considered.
2. Description of the Related Art
It is known to use a plurality of encoding modes to encode the same image. For example, blocks are formed in the image and a block is encoded according to the encoding mode which provides the best rate-distortion compromise.
However, each encoding mode has its own parameters, and it is difficult to obtain the same rate-distortion compromise with two different encoding modes for the same image.